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Subject Re: zlib inclusion and mod_gz(ip) recap
Date Sat, 08 Sep 2001 15:12:03 GMT

In a message dated 01-09-08 04:34:03 EDT, Justin wrote...

> On the zlib main site (
>  zlib is designed to be a free, general-purpose, legally unencumbered --
>  that is, not covered by any patents -- lossless data-compression library
>  for use on virtually any computer hardware and operating system. 
>  Not to say that they may not be wrong, but their view seems to be 
>  that zlib and its algortihms aren't covered by any compression 
>  patents.  I don't know if this helps at all.  -- justin


Since you are a self-described 'newcomer' to this list and
obviously you haven't searched the archives for the previous
discussions on this topic so let me say some things that have already
been said many times about this issue...

Take it all FWIW. Remember that IANAL.

There have been around 6 or 7 in-court challenges to the IP 
contained in the 'deflate' algorithm which is what both GZIP 
and ZLIB are based on. Most of them were in Europe but a 
few here in the USA. The ownership of LZ77 + Huffman has 
always been a weird piece of kit since IBM and Sperry Rand 
patented LZW and locked it up for themselves. Jean-loup Gailey 
and Mark ( Adler ) went backwards in time after the IBM patent 
issued to find the first ( but no the best ) implementation of LZ77 
that was patent-free and they used that for ZLIB to skirt the newly 
issued IBM patent.

None of the IP challenges have been successful so far ( E.g. ZLIB 
violates patents ) but they still crop up every now and anon.
The prevailing legal opinion is that Mark and Jean did the job
right and 'rewound' the technology far enough to be clear of the
IBM + Sperry Rand patent and other LZ claims. While deflate, GZIP 
and ZLIB will never even be near the best implementations of LZ around 
they are, in fact, 'patent free'.

But, as Ryan has said, that isn't the only issue.

Apache usually cares much MORE about being 'legally clean'
than just about any other public domain project ( some actually
could care less ) and the issue of 'other' patents probably
needs at least a fly-by or perhaps even a drafted opionion if it's time 
to actually have Apache 'use' or 'require' ZLIB. Only the Apache
board members can decide this one.

As Ryan described there are patents floating around that cover
even the actual 'concept' of delivering compressed presentation
layer content. We have paid our own IP lawyers thousands of
dollars to render opinions on these things but, as in most
real business situations, these opinions are not 'transferrable'. In 
other words... it would do no good for us to even forward our legal
findings to Apache. If Apache really wants a legal brief about
how these issues relate to Apache then only your own legal
work for hire can be applicable to/for your products.

ASIDE: A few of the legal challenges and one of the ongoing issues
surrounding any open source / public software is this whole
'least restrictive license shall apply' legal mumbo jumbo. 
Essentially, what that means is that there is always a chance
in a legal challenge that open source software which includes
other open source software could be held to the 'least restrictive
license in the work shall apply to the work as a whole'.

'Free' is supposed to be 'free' but unfortunately that isn't the
case in the open source world. Some groups like GNU and GPL
are following the 'We have to make it not totally free so that no
one can ever make it not totally free' sort of twisted logic and
there are some 'free' licenses that are still trying to 'restrict' 
what can be done with the code. The 'least restrictive license
shall apply to the work as a whole' clause simply means
that there is always a chance the more restrictive conditionals
could be ''removed'" from the work as result of legal challenge.

My own *advice* ( Evan though IANAL ) is not to worry about
these 'other' patents. No one else does.They basically fall into the 
same category as the guy who has the patent on the flashing 
cursor ( It's true ) and the guy who actually holds the HyperLink 
patent ( Also true... someone had a patent on clicking on something 
and having it 'go' somewhere else... long before Tim Berners Lees 
did the first HTML code drop ).

The odds that someone will suddenly need a royalty check in
this area are about as slim as CompuServe ever collecting 
money from anyone who creates a .GIF file ( CompuServe
holds the copyright on the .GIF format, always has. ).

Only your own IP lawyers can help you on this one if ALL the legal
implications of including ZLIB must be flushed out at this time.

I hope that helps.

See Apache's own archives for more about this.
It has been discussed many times on this forum.

Kevin Kiley

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